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Nexus 7K DHCP Snoop errors after adding 2nd dhcp relay address

Nexus 7K DHCP Snoop errors after adding 2nd dhcp relay address

Nexus 7K DHCP Snoop errors after adding 2nd dhcp relay address

Good morning,

We have 2 Nexus 7010's, Nexus-A in our main data center, Nexus-B out in our DR site. They are in a vPC configuration. Our main office has 4 IDF closets (stacks of 3750X), 2 closets upstairs/2 closets downstairs. All clostes are vPC'd to both Nexus'.
Yesterday, I added a 2nd DHCP Relay Address entry on both Nexus' for all 4 of the closet VLANS (112, 122, 132, 142). This relay is only for re-coring our machines across the seperate VLANs so that when we do PXE boot. As soon as I added the 2nd address, I began getting DHCP snoop (3) errors for the 4 closets on Nexus-B.

<Nexus-B-Data %DHCP_SNOOP-3-INVDHCPPKTS: Validation errors while processing DHCP packet received on interface Vlan122 vlan 0 Reason:DHCP length encoding over-flow.. Dropping the packet>

Nexus-A is configured exactly the same but has no errors. The only difference is, is that our server team does not have their UCS servers in a vPC configuration, so they are only located in our data center with Nexus-A. They are choosing to use an Active/Passive architecture and move VM servers as they need to. Nexus-B has all relevant configurations to accomodate their UCS.

The strange this is, I added this same 2nd DHCP relay address a few months ago and never had any issues. However, this time adding it, I see that the 2nd address (10.216.101.xxx) is now on top of the main DHCP server (10.216.110.xxx)

ip dhcp relay address 10.216.101.xxx
ip dhcp relay address 10.216.110.xxx

Do I need to force 10.216.110.xxx to be first on the list? If this is the case, why aren't I seeing this on Nexus-A? Any help would be appreciated!



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